devmap_map(9E) Driver Entry Points devmap_map(9E)NAMEdevmap_map - device mapping create entry point
SYNOPSIS
#include <sys/ddi.h>
#include <sys/sunddi.h>
int prefixdevmap_map(devmap_cookie_t dhp, dev_t dev, uint_t flags, off‐
set_t off, size_t len, void **pvtp);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI).
ARGUMENTS
dhp An opaque mapping handle that the system uses to describe the
mapping currently being created.
dev The device whose memory is to be mapped.
flags Flags indicating type of mapping. Possible values are:
MAP_PRIVATE Changes are private.
MAP_SHARED Changes should be shared.
off User offset within the logical device memory at which the map‐
ping begins.
len Length (in bytes) of the memory to be mapped.
pvtp A pointer to be filled in by device drivers with the driver
private mapping data.
DESCRIPTION
The devmap_map() entry point is an optional routine that allows drivers
to perform additional processing or to allocate private resources dur‐
ing the mapping setup time. For example, in order for device drivers
to support context switching, the drivers allocate private mapping data
and associate the private data with the mapping parameters in the
devmap_map() entry point.
The system calls devmap_map() after the user mapping to device physical
memory has been established. (For example, after the devmap(9E) entry
point is called.)
devmap_map() receives a pointer to the driver private data for this
mapping in pvtp. The system expects the driver to allocate its private
data and set *pvtp to the allocated data. The driver must store off
and len, which define the range of the mapping, in its private data.
Later, when the system calls devmap_unmap(9E), the driver will use the
off and len stored in pvtp to check if the entire mapping, or just a
part of it, is being unmapped. If only a part of the mapping is being
unmapped, the driver must allocate a new private data for the remaining
mapping before freeing the old private data. The driver will receive
*pvtp in subsequent event notification callbacks.
If the driver support context switching, it should store the mapping
handle dhp in its private data *pvtp for later use in
devmap_unload(9F).
For a driver that supports context switching, flags indicates whether
or not the driver should allocate a private context for the mapping.
For example, a driver may allocate a memory region to store the device
context if flags is set to MAP_PRIVATE.
RETURN VALUESdevmap_map() returns the following values:
0 Successful completion.
Non-zero An error occurred.
EXAMPLES
Example 1: devmap_map()implementation
The following shows an example implementation for devmap_map().
static int
xxdevmap_map(devmap_cookie_t dhp, dev_t dev, uint_t flags, offset_t off,
size_t len, void **pvtp)
{
struct xx_resources *pvt;
struct xx_context *this_context;
struct xx_softc *softc;
softc = ddi_get_soft_state(statep, getminor(dev));
this_context = get_context(softc, off, len);
/* allocate resources for the mapping - Device dependent */
pvt = kmem_zalloc(sizeof (struct xx_resources), KM_SLEEP);
pvt->off = off;
pvt->len = len;
pvt->dhp = dhp;
pvt->ctx = this_context;
*pvtp = pvt;
}
SEE ALSOdevmap_unmap(9E), devmap_unload(9F), devmap_callback_ctl(9S)
Writing Device Drivers
SunOS 5.10 7 Jan 1997 devmap_map(9E)
